Induction of alcohol dehydrogenase in explants of potato tuber (Solanum tuberosum L.).

During callus formation a huge increase in alcoholdehydrogenase activity was observed in potato tuber tissue discs. Callus formation was no prerequisite for this increase; slicing and subsequent incubation of potato tuber tissue discs always led to an increase in alcohol dehydrogenase activity, which was dependent on cytoplasmic protein synthesis. A three-fold increase was observed during incubation in moist air (periderm formation) and during incubation on nutrient agar without carbon source. A six- to eight-fold increase occurred during incubation on nutrient agar with sucrose, ribose or pyruvate as carbon source. The extra increase in alcohol dehydrogenase activity did not occur in the presence of equimolar amounts of mannitol, sorbitol, succinate or ethanol. The extent of the activity increase was not directly correlated with the presence of a carbon source suitable for maintaining growth.